skip to main content


Search for: All records

Creators/Authors contains: "Tiwari, Prabal"

Note: When clicking on a Digital Object Identifier (DOI) number, you will be taken to an external site maintained by the publisher. Some full text articles may not yet be available without a charge during the embargo (administrative interval).
What is a DOI Number?

Some links on this page may take you to non-federal websites. Their policies may differ from this site.

  1. Nanomaterials have unique properties, functionalities, and excellent performance, and as a result have gained significant interest across disciplines and industries. However, currently, there is a lack of techniques that can assemble as-synthesized nanomaterials in a scalable manner. Electrophoretic deposition (EPD) is a promising method for the scalable assembly of colloidally stable nanomaterials into thick films and arrays. In EPD, an electric field is used to assemble charged colloidal particles onto an oppositely charged substrate. However, in constant voltage EPD the deposition rate decreases with increasing deposition time, which has been attributed in part to the fact that the electric field in the suspension decreases with time. This decreasing electric field has been attributed to two probable causes, (i) increased resistance of the particle film and/or (ii) the growth of an ion-depletion region at the substrate. Here, to increase EPD yield and scalability we sought to distinguish between these two effects and found that the growth of the ion-depletion region plays the most significant role in the increase of the deposit resistance. Here, we also demonstrate a method to maintain constant deposit resistance in EPD by periodic replenishing of suspension, thereby improving EPD’s scalability. 
    more » « less
  2. Abstract

    The fabrication and characterization of the first magnetoelectric sensors utilizing arrays of Janus magnetoelectric composite nanowires composed of barium titanate and cobalt ferrite are presented. By utilizing magnetoelectric nanowires suspended across electrodes above the substrate, substrate clamping is reduced when compared to layered thin-film architectures; this results in enhanced magnetoelectric coupling. Janus magnetoelectric nanowires are fabricated by sol–gel electrospinning, and their length is controlled through the electrospinning and calcination conditions. Using a directed nanomanufacturing approach, the nanowires are then assembled onto pre-patterned metal electrodes on a silicon substrate using dielectrophoresis. Using this process, functional magnetic field sensors are formed by connecting many nanowires in parallel. The observed magnetic field sensitivity from the parallel array of nanowires is 0.514 ± .027 mV Oe−1at 1 kHz, which translates to a magnetoelectric coefficient of 514 ± 27 mV cm−1 Oe−1.

     
    more » « less